As the world's busiest container port, Hong Kong is a logical through point for smuggling drugs into the mainland, but it is not a major drug transit hub, security chief Ambrose Lee Siu-kwong insisted yesterday. Mr Lee said that as well as the record seizure of 550kg of ketamine in Tsuen Wan on Tuesday, police and customs had seized several consignments of drugs bound for the mainland, mostly ketamine, over the past year. Speaking after a meeting with the Fight Crime Committee to discuss the crime situation, the secretary for security said: 'I don't think Hong Kong is a transit hub for psychotropic drugs or heroin. Of course, Hong Kong is ... the busiest container port in the world. We cannot rule out that some illegal syndicates are trying their luck by using Hong Kong. 'The majority of ketamine is manufactured in the Indian subcontinent, moving through Malaysia, then to Hong Kong and onto the mainland. The mainland may be a developing market for psychotropic drugs.' The security chief said this week's seizure highlighted Hong Kong's zero tolerance for using Hong Kong as a transshipment point, as well as the city's successful exchange of intelligence with law enforcement counterparts overseas. 'Many of these successful operations are joint efforts of many law enforcement agencies and we will continue to work closely with our counterparts overseas to deal with drug syndicates and deal them heavy blows.' Crime figures for the first half of 2006, which were discussed by police and the Fight Crime Committee yesterday, showed that there had been an almost 20 per cent increase in the amount of ketamine seized between January and July this year compared to the same period in 2005. Mr Lee said there was a rising trend in the usage of ketamine and other psychotropic drugs among young people. He added that the number of serious crimes rose by as much as 8.6 per cent, including assault and wounding cases, and there was an increase in criminal intimidation.